Host-parasite tissue adhesion by a secreted type of \u03b2-1,4-glucanase in the parasitic plant Phtheirospermum japonicum

Ken-Ichi Kurotani,Yasunori Ichihashi,Satoshi Ogawa,Songkui Cui,Michitaka Notaguchi,Ken Shirasu,Yu Sawai,Koji Okayasu,Takanori Wakatake,Takamasa Suzuki

doi:10.1038/s42003-020-01143-5

Abstract

Tissue adhesion between plant species occurs both naturally and artificially. Parasitic plants establish intimate relationship with host plants by adhering tissues at roots or stems. Plant grafting, on the other hand, is a widely used technique in agriculture to adhere tissues of two stems. Here we found that the model Orobanchaceae parasitic plant Phtheirospermum japonicum can be grafted on to interfamily species. To understand molecular basis of tissue adhesion between distant plant species, we conducted comparative transcriptome analyses on both infection and grafting by P. japonicum on Arabidopsis. Despite different organs, we identified the shared gene expression profile, where cell proliferation- and cell wall modification-related genes are up-regulated. Among genes commonly induced in tissue adhesion between distant species, we showed a gene encoding a secreted type of β-1,4-glucanase plays an important role for plant parasitism. Our data provide insights into the molecular commonality between parasitism and grafting in plants.

Highlights

Tissue adhesion between plant species occurs both naturally and artificially
At the parasitization site in the root, a xylem bridge is formed in the haustorium (Fig. 1c), by which the P. japonicum tissues invade the host tissues (Fig. 1d)
Serial sections revealed a decrease in cell wall thickness at the interface between P. japonicum and Arabidopsis tissues (Fig. 1f–i), which indicated that cell wall digestion occurred at the interface

Summary

Introduction

Tissue adhesion between plant species occurs both naturally and artificially. Parasitic plants establish intimate relationship with host plants by adhering tissues at roots or stems. To understand molecular basis of tissue adhesion between distant plant species, we conducted comparative transcriptome analyses on both infection and grafting by P. japonicum on Arabidopsis. In the autotrophic plant lineage, parasitic plants have evolved the capability to absorb water and nutrients from other plants This ability relies on a specialized organ called a haustorium, which forms a physical and physiological connection between the parasite and host tissues[1]. Plant parasitism has independently evolved in angiosperm lineages at least 12 times and ~1% of angiosperms are estimated to be parasitic[2,3] Among these species, the Orobanchaceae family is the most species-rich and includes the notorious agricultural pests Striga spp., Phelipanche, and Orobanche spp., which threaten world food security[4]. The parasitic haustorium is able to adhere to the host tissues either in roots or in stems

Methods

Results

Conclusion